Abstract
Purpose: :
To test whether a Wavefront Sciences COAS Shack–Hartmann (S/H) wavefront sensor (SHWS) can be used to quantify intraocular scatter.
Methods: :
A physical eye model eye (7mm pupil) with and without cataract was mounted to the COAS unit. The model eye had two configurations. The standard configuration had a small diameter probe beam pass through the eye’s ocular media to form a retinal guide star that is reflected back out of the eye and into the SHWS. The single–pass configuration was such that the retinal guide star originated from the retina by illuminating a pinhole from behind the eye. The two configurations aided in distinguishing surface back reflections from forward scatter. Progressing densities of microspheres within a volume of water were located behind the model eye’s pupil to approximate a range of nuclear cataract of 0.1 to 6.9 using the LOCSIII system. The COAS system was modified to allow a wider acceptance angle for intraocular scatter. Surface back reflections were minimized or suppressed. Forward scatter metrics were applied to S/H images to quantify forward scatter.
Results: :
The forward scatter metrics were correlated to the progressive cataract density. Second moment spot size and other analysis metrics were considered.
Conclusions: :
The COAS can be used to quantify intraocular forward scatter.
Keywords: cataract • crystalline lens • clinical (human) or epidemiologic studies: systems/equipment/techniques